The present invention generally relates to improvements in water purification systems of the type having a reverse osmosis (RO) unit or the like for removing dissolved ionic material and other contaminants from an ordinary supply of tap water or the like. More particularly, the present invention relates to an improved water purification system having automatic flush flow for intermittently and automatically self-cleaning a reverse osmosis membrane and refreshing particulate catalyst matter in related pre- or post-filters.
Water purification systems in general are well-known in the art of the type having a reverse osmosis (RO) unit or membrane for converting an incoming supply of ordinary tap or feed water into relatively purified water for use in cooking, drinking, etc. In general terms, the reverse osmosis unit includes a semi-permeable RO membrane through which a portion of the tap water supply passes, such that the membrane acts essentially as a filter to remove dissolved metallic ions and the like as well as other contaminants and undesired particulate matter from the tap water. In normal operation, these impurities are removed from one portion of the water flow and concentrated in another portion of the water flow, commonly referred to as retentate or brine, which is normally discharged as waste to a drain. The thus-produced flow of relatively purified water is available for immediate dispensing for use, and/or for temporary storage within a suitable reservoir or vessel for later dispensing.
A pure water dispense faucet mounted typically on or adjacent to a kitchen-type sink or the like is manually operable to dispense the produced purified water. While the specific construction and operation of such RO water purification systems may vary, such systems are exemplified by those shown and described in U.S. Pat. Nos. 4,585,554; 4,595,497; 4,657,674; and 5,045,197.
One disadvantage associated with reverse osmosis water purification systems relates to the fact that retentate or brine outflow from the RO membrane is normally discarded as waste. As a result, many residential and commercial water customers have favored use of bottled water as a purified water source, despite the costs and inconveniences associated with delivery, storage and changeover of large (typically 5 gallon) water bottles with respect to a bottled water cooler.
Another disadvantage associated with reverse osmosis water purification systems relates to the typically limited service life of the RO membrane and other pre- and post-filter elements. Many RO systems use a pre-filter element typically including a carbon-based filtration media for initial removal of contaminants from a tap water inflow at a location upstream from the RO membrane. One important function of this pre-filter element is to remove contaminants that would otherwise shorten the operating service life of the RO membrane. A downstream-located post-filter element is also commonly provided for additional water filtration and purification before dispensing. This array of pre- and post-filter elements, in combination with the RO membrane, is often provided in the form of individual cartridges designed for facilitated disassembly from and re-assembly with a unitary-type manifold. See, for example, U.S. Pat. No. 5,045,197, the contents of which are herein incorporated by reference. Despite the fact that cartridge replacement may be required only once each year, and despite efforts to make cartridge changeover an intuitively simple process, many customers are reluctant to handle this task. Instead, replacement of the various RO system cartridges has largely remained the responsibility of a water service company, thereby entailing regular and relatively costly service calls to each customer's residence or place of business. The requirement for regular service calls dramatically increases the overall operating cost of the RO system, thereby reducing or eliminating apparent advantages relative to conventional bottled water coolers and related bottle delivery systems.
There exists, therefore, a significant need in the art for further improvements in and to water purification systems, wherein the service life of a reverse osmosis (RO) membrane and/or related pre- or post-filter elements are significantly extended for at least a period of several years without requiring attention by service personnel through. Such improvements include the use of a flush-flow activation chamber that intermittently facilitates rapid injection of tap water inflow over the RO membrane to wash away accumulated particulate matter and to refresh particulate catalyst matter in pre- or post-filtration cartridges that may clump together during periods of relatively slow tap water inflow. The present invention fulfills these needs and provides further related advantages.